Adhesive tapes are widely used in various fields. They are applied to adherend members having a wide variety of forms, so that the shape of adhesive tapes also varies widely.
One of the most difficult operations is that of applying a long adhesive tape to a designated position on an exterior surface of an automobile. This is because the exterior surface of an automobile body is in general a complicated curved surface and the adhesive tape is often non-linear in shape and non-uniform in the width. In addition, the operation of applying such an adhesive tape has to be performed while the automobile body is moving on the production line.
There is a case, for example, where an adhesive tape is to be adhered to an adherend surface that has a neighboring surface in linkage thereof via a folding line, keeping the side edge of the adhesive tape at a position separated by a predetermined distance from the folding line.
In such a case, the operator has to accomplish three tasks simultaneously, that is:
(1) to keep the position of the side edge at a constant distance from the folding line;
(2) to keep the unapplied portion yet to be applied and the liner of the adhesive tape from interfering with the application operation; and
(3) to apply the adhesive tape using a squeezee or the like.
Thus, the operation is very difficult, and air bubbles are often formed in the interface between the adherend surface and the adhesive tape.
When an air bubble is formed in the interface between the adherend surface and the adhesive tape, the adhesive tape has to be pulled off up to the position of the bubble and to be applied again. If this is repeated several times, the adhesive tape may become deformed or no longer marketable, depending on the tape. Or, dust may stick to the tape, leading to another problem. In addition, the operation may not be completed within the specified process time.
Thus, a frequently adopted approach has been to assign two workers to this operation, so that while one is holding the tape with appropriate tension, the other may confirm the parting line and proceed with the application of the adhesive tape. This has resulted in an increase in labor costs for such operations.